Illusory motion display devices and method of making same



SR' 5mm MW ILLUSORY MOTION DISPLAY DEVICES AND METHOD OF MAKING SAME Filed April 7, 1964 Z (v a 17AM) 15 igl 14 J 16 INVENTORS 72/0/1446 4 444/5, l V/LLMM A TOMA/41:04!

United States Patent 3,315,391 ILLUSORY MOTION DISPLAY DEVICES AND METHOD OF MAKING SAME Thomas H. Lane, Wayzata, and William E. Tomlinson,

Minuetonka, Minn., assignors to Anagraphic Corporation, Minneapolis, Minn., a corporation of Minnesota Filed Apr. 7, 1964, Ser. No. 357,891 9 Claims. (Cl. 40-10652) This invention relates to display devices. More particularly, it relates to display devices designed to show animation and the method for producing the same.

Modern advertising is becoming increasingly complex with ever greater emphasis being placed upon means for demanding and receiving the attention of the potential customer. Since motion has long been recognized as perhaps the best by far method of gaining at least the initial attention of the public, there has been an ever increasing demand for advertising display devices which successfully utilize motion in a realistic manner at a non-prohibitive cost. Our invention is directed toward fulfilling this demand.

It is a general object of our invention to provide a novel and improved display device of simple, safe, and inexpensive construction and operation and yet capable of producing illusory motion.

A more specific object is to provide a novel and improved display device capable of producing illusory motion in a realistic, simple and inexpensive manner through the use of polarized light.

Another object is to provide a novel and improved display device capable of producing illusory motion through the use of rotary polarized light and a replica of a form desired to be portrayed formed within a sheet of relatively inexpensive, transparent to translucent plastic material.

Another object is to provide a novel and improved display device capable of producing illusory motion through the use of rotary polarized light and having a minimum of initial cost and subsequent operational and maintenance expense.

Another object is to provide a novel and improved method of producing an unusually simple and inexpensive display device for creating, in conjunction with rotary polarized light, illusory motion in a form desired to be portrayed through a simple and inexpensive expedient.

These and other objects and advantages of this invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views, and in which:

FIG. 1 is a somewhat diagrammatic side elevational view of a display device embodying our invention;

FIG. 2 is a similar diagrammatic side elevational view of a second display device embodying the preferred form of our invention;

FIG. 3 is a perspective 'view of a die which we have utilized in practicing our invention; and

FIG. 4 is a vertical sectional view taken through vacuum-forming apparatus and illustrating usage of the same in accordance with our invention in the forming of the abnormal residual stress areas in a form to be portrayed.

In attempting to provide an inexpensive and long lasting display device with inherent animation, we have discovered that it is possible to create illusory motion in a form desired to be portrayed by creating such form by a particular method and from a particular type of material and then utilizing such form in combination with polarized light by placing the same between a fixed and a 3,315,391 Patented Apr. 25, 1967' rotary analyzer producing such polarized light. In other words, we have discovered that if it is desired to show motion, for the purpose of gaining the publics attention or for other purposes, it is possible to do so by pressureforming the form desired to be portrayed in a sheet of a particular kind of material while maintaining such sheet at its forming temperatures and subsequently cooling the same, thereby introducing a plurality of adjacent areas within the sheet and such areas having different residual internal stresses, the different internal stress areas serving to define the form desired to be portrayed. We have further discovered that upon placing such a formed sheet between a fixed and a rotary polarizer of light, illusory motion is created in such areas to provide an unusually pleasing and aesthetic effect which is highly desirable and valuable in an advertising item.

Wherever herein the term forming temperature or its substantial equivalent is used, it is intended to refer to that range of temperature (for the particular material to which reference is made or is being used) below which pressure-forming will create blush crazing or crazing within the material and above which the material will assume properties so nearly resembling a liquid as to preclude the introduction of such stress areas into the interior of the material as a-result of forming. In other words, the temperatures above such range would be those at which the material would so nearly resemble a liquid that it would merely flow into the die and assume its shape without creating any areas of substantial residual stresses within the interior thereof as a result of assuming its new shape.

Thus, we have discovered that we can not only create animation or illusory motion within the desired form to be portrayed but we can do this inherently and unex pectedly by creating the form in a particular manner.

We have found three polar light-permeable thermoa plastics which have proved very satisfactory in practicing our invention. Actually, it appears that many other products may function properly and that the list includes all light-permeable thermoplastic and thermo-setting materials capable of being pressure-formed into the outline of a form desired to be portrayed so as to leave abnormal residual internal stresses at the points of deformation. Polar light-permeable thermoplastics are the preferred materials to be used, however, because of their transparency, low cost, and physical characteristics which facilitate handling during the pressure-forming operation. In any event, the material should be at least translucent and generally preferably transparent.

We have found that cellulose acetate butyrate, acrylic, and general purpose polystyrene are three of the preferred materials with which to work. Of the three we prefer cellulose acetate butyrate with acrylic being a close second in choice. We have found, however, that with each material there are dependent variables which qualify optimum temperatures versus geometry and esthetics. For example, the thickness of the sheet of the material and the temperature of the air in the fabricating shop have definite effects upon the optimum temperature to which the material should be raised prior to the pressure-- forming operation. The greater the thickness of the sheet, the slower the material will cool and as a result more time may be taken in the actual forming operations. Likewise, the warmer the room temperature in the fabricating shop, the more time may be consumed in the fabrication of the desired form.

Likewise, the material from which the mold is made and its temperature are important. Since some materials conduct heat much more rapidly than others, therecan be a definite variation in the rate at which the forming material will be cooled by the mold. Thus a mold having a high rate of heat conduction will require that the temperature of the forming sheet 'be raised to a higher elevation than one which has a lower rate of conductivity, everything else being constant. Similarly, a cooler mold will cause the material to set more quickly and consequently under such circumstances the temperature at which the material is to be formed must be raised. If paints or the like are applied to the material to be formed, these too will somewhat affect the temperature to which the material should be raised prior to the actual forming operation.

Given below are two tables illustrating the effect of sheet thickness and room temperature and giving the formation time available under various conditions for cellulose acetate butyrate, and acrylic. Similar rheology data can be obtained on almost all materials which can be used for this purpose by contacting the fabricators or raw material suppliers of these particular compounds and reference should be made to them for such information when utilizing a different material.

MAXIMUM TIME AVAILABLE FOR FORMING CELLULOSE ACETATE BUTYRATE SHEETS IN STILL AIR BEFORE COOL BELOW MINIMUM FORMING TEMPERA- Ambient Temperature, F.

Sheet Thickness, Inch Initial Sheet Temperature, F.

FOR FORMING ACRYLIC EY COOL BELOW MAXIMUM TIME AVAILABLE SHEETS IN STILL AIR BEFORE TH As will be seen by reference to the above charts or tables, in the case of acrylic, temperatures used in the formation of the desired form range in the neighborhood of 230-360 degrees F., depending on the grade and thickness used. Temperatures less than 275-230 degrees F. may result in excessive internal stress with possible crazing and eventual changes resulting from the forming operation if the room temperature is not high enough or if the sheet of material is too thin. If the forming is not completed at or above these temperatures, the parts will be cold formed and thereby cause crazing from such resultant excessive residual stress. Such excessive stresses cannot normally be removed by annealing without causing significant deformation of the part. The heated acrylic sheets must be completely formed before their surfaces and internal temperatures drop below 275-230 degrees F., depending on the grades of the material.

We have found that various methods of pressure forming of the e t o plastic material m y e ut ized a1- though, generally speaking, we prefer the vacuum-forming process wherein we apply the sheet of plastic material which has been heated to its forming temperature to a vacuum-forming mold and subject it to vacuums within the range of 22 inches-27 inches of mercury.

However, positive pressures may be applied to the so" heated sheet of material within a range of approximately 50-100 p.s.i. to provide excellent results. Also, if desired, the desired form with the required stresses may be produced through the use of injection molding processes wherein the material is injected into the necessary die of the proper form.

In the case of cellulose acetate butyrate, the minimum sheet temperature with which reliable mold reproduction may be expected is approximately 220 Reference to the above table shows the amount of time available for the actual forming operation for sheets of different thicknesses when heated to one of three given temperatures within the forming temperature range.

In the case of general purpose polystyrene which is one of the polystyrene complexes, the forming temperature range is approximately 250-320 degrees F. with the preferred forming temperature at approximately 300 F.

We have found that the preferred or optimum forming temperature of acrylic is approximately 320, F. The preferred or optimum forming temperature of cellulose acetate butyrate appears to be approximately 285 F.

While it appears that many other thermoplastic and thermosetting materials will, upon similar pressure-forming, produce results somewhat similar to those described herein, it must be borne in mind that in order to function properly in a display device the material from which the desired outline to be portrayed is formed must retain such internal stresses and must not gradually permit such stresses to fade or be relieved. In other words, these internal stresses must be permanent. Therefore, wherever herein the term residual is used it is intended to connote permanent interior stresses set up as a result of the forming operation within the material and defining the outline of the form to be portrayed. Moreover, the material to be used must be of a type which will retain such inherent stresses and will not permit them to be relieved through cold flow of the material.

In the drawings we have illustrated various aspects of our invention. In FIG. 1 we have shown a source of artificial light such as a lamp 5 with its light directed toward a rotatably mounted polarized disc or polarizer 6. This disc 6 is connected in driven relation to a motor 7 which rotates the same. Directly ahead of the rotatable polarizer is a second sheet of polarized material or polarizer 8 commonly referred to as an analyzer. Between the two polarizers 6 and 8 is a rigid sheet 9 of lightpermeable substantially non-elastic polar thermoplastic material which has a plurality of adjacent areas 10 therewithin which have fixed abnormal residual stresses of different magnitudes.

In FIG. 2 we have shown the same elements as those used in FIG. 1, which is our preferred form of the invention. -In FIG. 2 the fixed polarizer 8 is disposed between the sheet 9 and the light 5 while the rotatable sheet or disc 6 is disposed behind the sheet of formed thermoplasic 9.

In FIG. 3 we have shown a male die 11 which may be used in the forming operation of a particular display device such as shown and identified by the numeral 9 in FIGS. 1 and 2. As shown it is a male die constructed so that its forming surface is provided with a plurality of upstanding rectangularly shaped protrusions '12 shaped and arranged to resemble a bed of ice cubes. The die 11 may be made of wood, metal, or any other suitable die material. When using such a die the thermoplastic sheet of material from which the display device is to be formed will be placed upon the upper surface of the die 01 after having been first heated to a temperature well within its forming range. The weight of the thermoplastic material will be ample to cause that sheet of material to stretch around the contour of the die 11 and thereby create the adjacent areas .10 of residual internal stress of different magnitudes. If desired, positive pressure may be applied to the upper surface of the sheet of plastic material to urge the plastic to conform to the contours of the die and thereby create the areas of residual internal stress. It will be noted that the areas of greatest internal residual stress L2 will define the outline of the form to be portrayed, in this case, a bed of ice cubes. Once the sheet has assumed the form of the die it is permitted to cool to ambient temperatures which, of course, should bebelow the minimum forming temperature of the material from which the sheet 9 is made.

The preferred method of producing the form desired to be portrayed from the sheet of light-permeable themoplastic material is shown in FIG. 4. -In FIG. 4 conventional vacuum forming apparatus 13 is used with the manifold 14 connected by a hose 15 to a source of negative pressure or vacuum (not shown). The die '16 is shown to have a contour resembling a bed of ice cubes similar to that of die 11 andit is provided with a plurality of vacuum ports 17. The sheet of polar light-permeable thermoplastic is first clamped into a frame (not shown) around its periphery and then heated in an oven until it reaches the desired forming temperature at which time it is removed from the oven and applied to the upper surface of the die 16, the frame being sufficiently large to surround the die and, as a result, create an effective seal at the periphery of the die. The sheet of thermoplastic material becomes highly flexible as a result of the heating to which it is subjected and, when applied to the die surface, seals therewith around its periphery so that upon application of vacuum therebelow by the apparatus 113, the sheet 18 will be drawn down around the protrusions 19 to create the adjacent areas 20 of residual stress of different magnitudes.

When such a sheet 18 of pressure formed thermoplastic is positioned similarly to the sheet 9 as in FIG. 1 and FIG. 2, so as to be disposed between a fixed polarizer 8 and a rotary polarizer 6, illusory motion will be produced by the light passing therethrough within the stress areas 20 defining the outline of the form to be portrayed as contained in the sheet .18. The intensity of the light in these areas of different stress varies as the polarizer 6 rotates with the net result that an illusion of motion is created for the observer.

The net result is a very pleasing and esthetic effect which has been shown to be in demand in advertising or other display devices where motion is considered desirable or even imperative. While some slight color may upon occasion be evidenced in the stress areas, it is slight and can easily be overcome through the use of a color filter which will provide any color desired in the form to be portrayed. For example, a blue color filter placed between the observer and the sheet 9 imparts a beautiful effect to the appearance of the ice cube bed form while constant and apparent random motion is evident throughout the form.

It will be readily appreciated that a display. device constructed in accordance with our invention is relatively simple and inexpensive to manufacture, maintain, and operate. Moreover, a highly desirable etfect heretofore unknown and unobtainable is produced. For example, when a replica of a bottle or can of a drink such as soda, beer, etc. is placed within a form such as shown in FIGS. 1-2, a very inviting and appealing vision is presented to the viewing public. 'It will be readily seen that there are many other varied uses to which such a device may be put and that, therefore, the advantages of such a device are many fold.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of this invention which consists of the matter shown and described herein and set forth in the appended claims.

What is claimed is:

1. An illusory motion display device comprising:

(a) a rigid substantially non-elastic sheet of polar thermoplastic light-permeable plastic material having a plurality of adjacent areas therewithin having fixed abnormal residual stresses of different magnitudes,

(b) a rotatable sheet of polarized light-permeable material mounted for rotation at one side of said sheet of plastic material for rotation in a plane generally parallel to the general plane of said sheet of plastic material,

(c) means connected to said sheet of polarized material for rotating the same,

((1) a fixed sheet of polarized light-permeable materialdisposed at the opposite side of said sheet of plastic material and extending generally parallel to said other two sheets, and

-(e) a source of artificial light positioned relative to said three sheets of material so that the light therefrom will pass therethrough as said rotatable sheet is rotated whereby an illusion of motion in said sheet of plastic material will be created by the light passing therethrough.

2. The structure defined in claim 1 wherein said areas of different magnitude of residual stresses define the outline of a form to be portrayed.

3. The structure defined in claim 1 wherein said sheet of plastic material is comprised of cellulose acetate butylate.

' 4. The structure defined in claim 1 wherein said sheet of plastic material is comprised of a polystyrene complex.

5. The structure defined in claim 1 wherein said sheet of plastic material is comprised of methyl methacrylate.

6. An illusory motion display device comprising, a source of light, a rotatable sheet of polarized transparent material mounted for rotation ahead of said light source in position so that the light therefrom will pass therethrough, as said sheet is rotated, means for rotating said sheet, a sheet of transparent rigid substantially non-elastic thermoplastic material disposed ahead of said rotatable sheet of polarized material in the path of the light passing therethrough and extending generally transversely thereof, and a sheet of polarized transparent material disposed on the side of said sheet of plastic material opposite to said rotatable sheet of polarized material, certain areas of said sheet of transparent rigid thermoplastic material being maintained under fixed abnormal internal stress of different magnitudes whereby an illusion of motion is created therein by the light cast thereupon by said source through said rotatable sheet of polarized transparent material.

7. An illusory motion display device comprising:

(a) a rotatable sheet of polarized light-permeable material mounted for rotation about a central axis thereof,

(b) means connected to said sheet for rotating the same,

(c) a sheet of polar thermoplastic light-permeable plastic material disposed at one side of said rotary sheet and extending generally parallel thereto,

(d) a second but fixed sheet of polarized light-permeable material disposed at the opposite side of said sheet of plastic material and extending generally parallel thereto, and

(e) a souce of light positioned relative to said sheets so that the light therefrom will pass through said sheets as said rotatable sheet is rotated,

(if) certain areas of said sheet of thermoplastic lightpermeable plastic material having a plurality of adjacent areas thereof which have abnormal residual stresses of different magnitudes therein whereby an illusion of mot-ion is created therein by the light 7 passing therethrough as said rotatable sheet is rotated.

8. An illusory motion display device oomprising:

(a) a source of artificial light,

(b) a sheet of rigid substantially non-elastic polar thermoplastic light-permeable plastic material disposed ahead of said light source in position so that the light therefrom will pass therethrough,

(c) a pair of sheets of polarized light-permeable material mounted adjacent to and at opposite sides of said sheet of plastic material in position so that the light from said light source will pass therethrough,

(d) one of said sheets of polarized light-permable material being mounted for rotation with the light from said light source passing therethrough,

(e) certain adjacent areas of said sheet of polar thermoplastic light-permeable plastic material being contoured and having fixed abnormal residual internal stresses of different magnitudes whereby an illusion of motion is created in said areas by the light passing therethrough while said rotatable sheet of polarized material rotates.

9. An illusory motion display device comprising:

(a) a rigid substantially non-elastic light-permeable sheet of material of the type capable of being pressure-formed into an outline of an object desired to I be portrayed, and of retaining residual stresses therein, (b) said sheet having a plurality of adjacent areas therewithin having fixed abnormal residual stresses of different magnitudes,

(c) a rotatable sheet of polarized light-permeable material mounted for rotation at one side of said sheet of plastic material,

(d) means connected to said sheet of polarized material for rotating the same,

(e) a fixed sheet of polarized light-permeable material disposed at the opposite side of said sheet of non-elastic material, and

(f) a source of artificial light positioned relative to said three sheets of material so that-the light therefrom will pass therethrough as said rotatable sheet is rotated whereby an illusion of motion will be created in said sheet of non-elastic material by the light passing therethrough.

References Cited by the Examiner UNITED STATES PATENTS 2,473,857 6/1949 Burchell 40-130 X 2,838,864 6/1958 Guidce 88-65 X 2,977,845 4/196-1 Boone 40-130 X 3,046,839 7/1962 Bird 8865 3,052,153 9/1962 Powell 88-65 X 3,054,204 9/1962 Yates 88-65 X 3,104,273 9/1963 Ballance 40-10653 X EUGENE R. CAP-OZIO, Primary Examiner.

30 H. F. ROSS, Assistant Examiner. 

6. AN ILLUSORY MOTION DISPLAY DEVICE COMPRISING, A SOURCE OF LIGHT, A ROTATABLE SHEET OF POLARIZED TRANSPARENT MATERIAL MOUNTED FOR ROTATION AHEAD OF SAID LIGHT SOURCE IN POSITION SO THAT THE LIGHT THEREFROM WILL PASS THERETHROUGH, AS SAID SHEET IS ROTATED, MEANS FOR ROTATING SAID SHEET, A SHEET OF TRANSPARENT RIGID SUBSTANTIALLY NON-ELASTIC THERMOPLASTIC MATERIAL DISPOSED AHEAD OF SAID ROTATABLE SHEET OF POLARIZED MATERIAL IN THE PATH OF THE LIGHT PASSING THERETHROUGH AND EXTENDING GENERALLY TRANSVERSELY THEREOF, AND A SHEET OF POLARIZED TRANSPARENT MATERIAL DISPOSED ON THE SIDE OF SAID SHEET OF PLASTIC MATERIAL OPPOSITE TO SAID ROTATABLE SHEET OF POLARIZED MATERIAL, CERTAIN AREAS OF SAID SHEET OF TRANSPARENT RIGID THERMOPLASTIC MATERIAL BEING MAINTAINED UNDER FIXED ABNORMAL INTERNAL STRESS OF DIFFERENT MAGNITUDES WHEREBY AN ILLUSION OF MOTION IS CREATED THEREIN BY THE LIGHT CAST THEREUPON BY SAID SOURCE THROUGH SAID ROTATABLE SHEET OF POLARIZED TRANSPARENT MATERIAL. 